Harrison (pictured) said last month the industry should take a "responsible attitude" towards the increasing number of children using mobile phones by marketing targeted products to them in a sensible manner.

Carphone’’ Mobile Life report said mobile phones are increasingly becoming communications tools for the very young.

The Stewart Report, an expert study of the health risks of mobile phones on the young from 2005, put pressure on the industry not to promote phones to under 16s.

Children’s charities say the more ethical approach would be to market to parents.

Child Net deputy chief executive Will Gardner said: "Parents should be given the choice of what type of mobile phones to give their child.

"We have to make sure that they use their phone safely and parents know what services are on offer."

National Children’s Home (NCH) head of safeguarding children Shaun Kelly said: "Quite a lot of children these days have phones so the phones they use should have less functionality.

“If young children are going to have phones they should have ones that are safe for them.”

But manufacturers and retailers – the few who agreed to speak to Mobile News on the matter – still feel this is not ethical.

Sony Ericsson marketing director Dave Hilton said: "We do not target children and do not promote phones to under 16s.

“We recognise teenagers use phones, but we have adopted the ethical policy not to target them.

“If it is found that there is an increasing market appetite and we believe there are no ethical implications at that time then we would consider targeting under 16s."

A Phones 4U spokesperson said: "Whilst it is clear the use of mobile phones by children is on the increase, we must remember that child safety is paramount.

“We understand there is a need in society today for more stringent controls regarding how mobiles are used by children, and the content they are able to access.

"However, Phones 4U’s core target market are 16-24 year-olds, and so all of its marketing efforts are focused on reaching those over the age of 16."